This document describes new or enhanced features of STAAD Foundation Advanced (SFA) since the CONNECT Edition V9.2 (Release 184.108.40.206).
In the General and Toolkit modes of SFA, load combinations can now be generated per the ASCE standard titled
ASCE 7-16 - Minimum Design Loads and Associated Criteria for Buildings and Other Structures
In order to generate combinations using this code, the basic load cases need to be assigned one of the following types in SFA.
The combination cases generated by SFA are in accordance with Section 2.3 of the ASCE 7-16 document for Strength Design, and, Section 2.4 of that document for Allowable Stress Design. Recall that for foundation designs based on the ACI 318 code, the concrete design of foundations must be based on combination cases for strength design, while soil pressure and stability checks should be done using combination cases for allowable stress design. (Strength cases are also referred to by the name Ultimate cases in SFA.)
In SFA, a facility for generating these combinations is available in the General mode and in the Toolkit mode, with separate buttons for service and strength. Each mode of the program contains a table that comes populated with the factors for the respective load types. The following figure shows the facility that is available in the General mode.
In those instances where a certain load type is a candidate for both signs (positive as well as negative), multiple load combination cases, that account for all combinations of the sign, will be generated. Wind, Seismic, Wind on Ice, etc. are the basic cases that fall in this category. For example, a combination of Dead load with 0.6*Wind Load will produce the following combinations
D + 0.6Wx
D + 0.6Wz
D - 0.6Wx
D - 0.6Wz
where D is Dead, Wx is Wind Along X, and Wz is Wind along Z.
Notice in the above figure that there is a check box in the second column, which if unchecked, instructs SFA that the combination case defined by that row should not be generated.
Some examples are Wind on Ice (without any direction), Ash Mass, Crane, etc. However, these types are not mentioned in the ASCE 7-16 document, and consequently, there are no load factors available in the load combination table in SFA for that code. As a result, if we assign those types to any of the basic load cases, they will be excluded from the generated combinations. Users can avoid this by setting their type to the ones named User1, User2, etc. and providing a factor in the table under those headings. A warning to alert the user to this possibility is reported by the program if such a situation is encountered.
STAAD Foundation Advanced now supports the standards for foundation design for China GB 50007-2011 Code for design of building foundation for the analysis and design of combined footings.
This feature is available through the General mode of the program. In the Toolkit mode and PLANT mode, the Chinese code is currently not available for these or other types of foundations.
How does one create a combined footing job?
In the section titled What’s New in CONNECT edition V9.1, the procedure used for creating an isolated footing job to the Chinese code was described.
The same procedure can be used to create a combined footing job.
The rules for performing the concrete design of the footing are similar to those for other codes. Users are urged to go through the various sections of the Technical manual for information on this topic.
The sections of the GB 50007 code that are used in performing the various checks for combined footings are similar to those for isolated footings, and those are available as shown in the topic highlighted in the next figure.
If the design of the footing is successful, a calculation sheet is displayed containing the details for the checks mentioned above, and the governing load case for each check. For a failed design, the cause of the failure has to be interpreted by reading the messages displayed in the Output Pane, which is the panel below the drawing area.
The report can be obtained in either Chinese or English.
Drawings of the foundation plan and layout are also produced.
Two solved examples that illustrate the procedure used for designing these footings is available in the verification manual of this program.
The SFA models for these examples are available in the Examples folder.
For all the foundation types in SFA for which design can be performed per the metric editions of the ACI 318 code, the reinforcing bar database that is used henceforth is per the specifications of that edition. Most of these editions have an Appendix where the bar details are listed. Shown here is the one for the 2011 edition.
For all the foundation types in SFA for which design can be performed per the Australian code AS3600-2018, the reinforcing bar database per the Australian standards is now available. The source of this information is the Australian standard AS/NZS 4671:2001 with Amendment No.1
For the pilecap module, in the various places where the pile arrangement is available in pictorial form, each pile is now annotated with a number for quick identification. This enables easier correlation between the pile and the forces in the pile as reported in the tables for oneway shear, punching shear, etc., in the calc report.
For mat foundations on piles, a table that shows the pile reactions for all the piles of the current mat job for the selected load case is now available for viewing from a table named Pile Reactions in the output pane. Please note that the selected load case should be part of the current mat job if its reactions are to be displayed. This is because, the reactions are calculated only for those load cases which are included in the job and analyzed. Hence, if the selected load case it is not included in the job, the table will be blank for that case.